Collapsible stroller



FIG. 1 is a perspective view of a collapsible stroller showing my new design;

FIG. 2 is a side elevation view thereof, the opposite side being a mirror image of that shown;

FIG. 3 is a top plan view thereof;

FIG. 4 is a front elevation view thereof;

FIG. 5 is a rear elevation view thereof; and

FIG. 6 is a bottom plan view thereof. 

The ornamental design for a collapsible stroller, as shown and described. 